Apple scab first appears as small, olive-colored lesions on the undersides of the leaves. As the fungus spreads, the top sides of the leaves develop lesions, as well, that may become black or mottled with defined edges. Severely infected trees may become defoliated by mid-summer, making the tree vulnerable to other diseases. The fruit develop black or brown scabs or soft areas.
cytosis. [ 1 sÄ«tÅâ²sis] 2  a condition in which there is a greater than normal number of cells in a tissue or organ.
Cytokinesis (cyto-kinesis) - the division of a cell into two distinct cells. This division occurs at the end of mitosis and meiosis. Cytotoxic (cyto-toxic) - a substance, agent, or process that kills cells. Cytotoxic T lymphocytes are immune cells that kill cancer cells and virus-infected cells.